NET ZERO METRICS
how to measure when your house produces equal to or more than the energy it consumes?
Net Zero Metrics - The Importance of Energy Modeling
When we bought the house and hired Susan and David Scott as our architects, we wanted a beautiful adapted to living in the 21st C and highly energy efficient. design. At the outset we did not ask for net zero (or even know what that meant). We put the original plans out to bid, and all the contractors based their proposals on time and materials - none offered fixed bids. We had a finite budget. It became apparent that to hit our number many of the bells and whistles we thought would make the house highly efficient would be ash canned. This made us very unhappy. Building on the island is expensive. We did not want to spend a fortune , only to end up with a house that was pretty but not green. We put a hold on the project and our tail between our legs. As you will read elsewhere, we were rescued by a veteran of old house net zero reno. Matt Grocoff said of course, we could do green reno. What’s more we could get to net zero and do it without resorting to the use of toxic materials or considerable extra expense. That this might be achievable was exciting, and affirming if a bit mysterious. Matt recommended we work with Niels Anthonsen, the founder of Enerylitics here in Victoria to get an energy model .Niels began by asking us a lot of questions about how we wanted to live so that the model he delivered would provide comfort as we define it. (Your standard may be different than ours.) Some people are comfortable walking around the house in slippers and a sweater much of the year - others require more warmth. PUT IN MORE BUTTON to CONTINUE THE TEXT
What is an energy model and how is it done?
Essentially an energy model is a picture of the house as it is, imagined anew in various ways (scenario management) that make it much more energy efficient. For a general overview of how modeling works I turned to Energy Models.com, a site for professional modelers. Here’s the poop - explained by Chris Balbach someone with plenty of street cred.
“There are many 'calculators' i.e.energy tools that can be applied for residential energy modeling and predictions of
savings. Most of them use 'simplified' algorithms or bin types of analysis. One example is TREAT (Targeted Retrofit Energy Analysis Tool) a software that simulates energy usage in single and multifamily residences. …
TREAT integrates a billing analysis module, (i.e.you submit your bills) which allows users to import both actual electric and fuel bills along with matching real weather data, create a baseline model, and then interactively adjust the 'baseline' model's predicted energy use to closely match amounts of energy and fuel consumed by the structure using “weather normalized” bills. In addition, once the user has created a 'trued-up' baseline model, TREAT provides a easy to use scenario management tool which allows for easy generation of improvements and packages (collections of improvements) with a focus of identifying packages with the most cost effective results (in other words , best cost-benefit ratios). Finally, the tool has an easy interface to allow for post-construction utility bills and post construction actual weather to be imported, where output from the model used to predict energy savings can be compared to actual energy savings, fuel by fuel, to verify the predicted savings are being delivered (or more importantly quickly
identify if they are not). This can be done after month one of post construction, giving 'fast feedback' to the homeowner as to whether the improvements they invested in are having the desired energy savings impact.”
We started with a blower test (measure of leakiness), and factored in a series of scenarios in which the insulation applied, window
orientation solar..
According to the site contractors can be trained to model single family homes in TREAT in 2 hours or less (from the time they sit down for data input to the time they produce a comprehensive work scope and proposal for a homeowner). It can be a powerful energy prediction and monitoring tool in the hands of a competent user. CHRIS BALBACH
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We have an 1800 square foot house.. Our plans are designed by Scott & Scott Architects on the footprint of the 1911 Edwardian vernacular arts & crafts style house. The renewed house will fossil fuel-free. Energy will be generated by solar panels on the south facing roof. Materials used in the renovation are to the greatest extent possible local, repurposed, salvaged, second-hand and free of toxins. During demo we tried to minimize material carted to the dump. One way we did this was to leave the old siding on the house - using it as a form of insulation. We gave away the old windows and scrap wood.
There are many steps to getting to net zero, we chose to tackle them all at once in a deep reno. We are showing them step by step - by category - you can adapt as you see fit for your own renovation. Our energy advisor. Mark Bernhardt is an experienced passive haus builder and consultant. We chose, at the suggestion our net zero guru, Matt Grocoff, to follow International Living Future Institute standards which are performance-based. It took almost two years of studying, futzing around, and recalculating to get to the point when we were ready to begin the build. We found Matt about a year into the exploratory. He did the first net zero reno of an old house in the US more than a decade ago.
That our architects David and Susan (and Olivia) stuck with us while we wandered in the wilderness and were congenial about letting their design become our experiment is something for which we will always be grateful. Their instinct is to design pretty mean and green to begin with.
That the Victoria mayor, Lisa Helps (a dead ringer for Rachel Maddow) embraced our endeavor and named us climate champions while John Ho to advise and cheerlead us along the way - emboldened us to do the right thing as much as we humanly could. Through City Green we got special help from bc home energy coach Chandra Horth, became their one and only Civic Engagement Project (chutzpa helps!). It will be an honor to give tours through them when the house is done. Be sure to check it out at BetterHomesBC.ca to understand rebates, and take advantage of their excellent FREE coaching service.
If you can do only one thing on the path to net zero now, and you have an oil tank, please remove it and replace it by an electric heat pump. That is the single most important step you can take to reduce the carbon footprint of your house. The city of Victoria has incentives to encourage elimination of oil tanks. Check them out.
We were guided by the belief that
the most sustainable building is the one that already exists
it’s not sustainable if its not affordable (We need a Green New Deal for homeowners!)
high performance can be arrived at without sacrificing aesthetics
With that let’s just dive in….
Don’t Do Anything Until You Have Performed a Blower Test
The first thing you want to know is just how leaky your house is and identify the leakiest spots.
As the ENERGUIDE RATING REPORT shows we had generalized problems adding up to a leakage rate of 14.42 air changes/hour. We’d need to get that figure way way down - since the fewer air changes per hour, the more air tight the building, the less heating we’d need. With our climate heating is only needed about half the year. Imagine that in Canada!
Take your blower test results, combine them with analysis of how much solar power you can generate, line that up with the demand that the lighting, appliances & heating/cooling systems will require. Then you will know how insulated your walls and windows need to be . Finally, Incorporate into this scheme a system to properly ventilate your house for health and comfort. (GRAPH)
Our Energuide (aka blower) test was done by City Green, energy savings specialists here in Victoria at the direction of Adam Campkin and Niels Anthonsen of Enerlytics. Later energy modeling has been performed by Mark Bernhardt of Bernhardt Contracting. We will likely do two more blower tests before we wrap up the build.
How is a blower test is conducted? This five minute Fine Homebuilding video will give you the lowdown. It is one of the most useful home diagnostic tools we have.
How is an energy model put together? - We asked Adam Campkin engineer who modeled our house in the spring of 2019. POST AS ADAM EXPLAINS TO WENDY
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The first conversation with Matt Grocoff our energy guru turned us on to many of these net zero principles and people skilled in analytics here on the island . Matt of Ann Arbor suggested we get in touch with Niels Anthonsen for modeling, Mark Bernhardt for building, that we follow International Living Future Institute guidelines for performance standards and avoid toxic ingredients. Not bad for a day’s work. We met island architect, Ken Choii through 475 Performance Building Supplies, then encountered Ken again at the International Living Futures Conference in Seattle. His Net Zero project in Cowichan Bay - Green Point Collaborative is stunning and inspiring. Have a look.
We met Taylor McCarthy, of Frontera Contracting via Mark Bernhardt who is his mentor. Taylor has an interest in green renovations and historic restorations. In our project he gets a bumper crop of both. We have asked a lot of him and he and his team have moved mountains to get this project going. In month four of the build Taylor had to cope with a pandemic. Thank you Taylor for toughing it out and finding ways to persevere safely. b
The photo above was taken at Green Point Design Collective.- Architect Ken Choii was kind enough to allow us to see what 475 High Performance Building Supply (thank you Shaun St Amour) was up to when a blower test was being conducted to make sure that the house was as air tight as needed to get to net zero. In this case the insulating material had been applied and the blower test was done to check for any leaks in the “armor”. Ken’s house in Cowichan Bay and a marvel of beauty. He’s going for multiple petals in International Living Future Institute award system.
NET ZERO METRICS - WHAT WE ARE UP TO